Problem: Subtract.
Answer: There are many ways to solve this problem. Let's see two ways we can solve it. Place Value We can think in terms of tenths: $\begin{aligned} &\phantom{=}33-16.8\\\\ &=33.0-16.8\\\\ &=330\text{ tenths} - 168\text{ tenths}\\\\ &=162\text{ tenths}\\\\ &=16.2 \end{aligned}$ Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths $3$ ${3}$ $.$ ${0}$ $1$ $6$ $.$ ${8}$ Now, let's subtract each place value column. Tens Ones $.$ Tenths $\overset{2}{\cancel{3}}$ $\overset{12}{\cancel{{3}}}$ $.$ $\overset{10}{\cancel{{0}}}$ $-$ $1$ ${6}$ $.$ ${8}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $1$ $6$ $.$ $2$ $16.2 = 33 - 16.8$